15 Aquilae
A K-type giant star faintly visible in the constellation Aquila.
15 Aquilae, also cataloged as h Aquilae, is a star located in the equatorial constellation Aquila. It has an apparent visual magnitude of 5.41, making it just barely visible without a telescope. About 39 arc seconds away lies an optical companion star designated HD 177442. Based on an annual parallax shift of 11.27 milliarcseconds, 15 Aquilae is roughly 289 light-years from Earth, give or take about 9 light-years.
Classified as a K1 III giant, this star is approximately four billion years old. Its outer atmosphere has expanded to about 14 times the Sun's radius, and it shines with 83 times the Sun's luminosity. With an effective temperature of 4,560 K, it emits the orange glow characteristic of a K-type star.
15 Aquilae is likely a member of the Milky Way's thin disk population. It orbits the galaxy with an eccentricity of 0.06, ranging from 24.30 thousand light-years to 27.60 thousand light-years from the Galactic Center. Its orbital path stays within about 196 light-years of the galactic plane.
Quick Facts
- Bayer designation
- h Aquilae
- Apparent visual magnitude
- 5.41
- Distance from earth
- approximately 289 ly (with a 9-light-year margin of error)
- Stellar classification
- K1 III
- Radius
- 14 times the Sun's radius
- Luminosity
- 83 times the Sun's luminosity
- Effective temperature
- 4,560 K
- Age
- roughly four billion years
Facts from the source article.
Lore & Background
15 Aquilae is a giant star of spectral type K1 III, having expanded to 14 times the Sun's radius after exhausting its core hydrogen. Its outer atmosphere radiates 83 times the Sun's luminosity at an effective temperature of 4,560 K, giving it the orange hue characteristic of K-type stars. The star is estimated to be roughly four billion years old. Its distance from Earth is approximately 289 light-years, derived from an annual parallax shift of 11.27 mas, with a margin of error of 9 light-years. An optical companion, HD 177442, is visible 39 arc seconds away, though it is not physically associated.
Reader's Guide
15 Aquilae is most likely a member of the thin disk population of the Milky Way. It orbits the galaxy with an eccentricity of 0.06, ranging from 24.30 kly to 27.60 kly from the Galactic Center, and its orbital inclination carries it no more than 196 ly from the galactic plane. As a K1 III giant, it represents a late stage of stellar evolution, having expanded and cooled after leaving the main sequence. Its faint naked-eye visibility (magnitude 5.41) and optical companion make it a target for amateur observers with small telescopes. The star's designation as both a Flamsteed and Bayer object (15 and h Aquilae) reflects its historical cataloging. Its thin-disk membership and low orbital eccentricity suggest it formed within the galactic disk and has remained in a relatively circular orbit.
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